The existing power switches use electromagnetic operating mechanism or spring operating mechanism to perform switch-off and switch-on actions. The electromagnetic operating mechanism has deficiencies in that it requires additional mechanical locking device, and has complex structure, high failure rate, high noise level and short service life. The spring operating mechanism requires being driven by a motor and locked in mechanical mode, with complex structure, heavy weight, slow movement, high noise level and high failure rate. In addition, a permanent magnet monostable operating mechanism has been developed in recent years, which has a more complex structure than a bistable one, especially the manual switch-off device of which still basically adopts conventional releasing principle, with large number of parts and complex structure that cause frequent malfunction of the locking part. The manual switch-off devices of the above operating mechanisms all operate with the normal actions of the mechanism, and has short service life due to frequent operations. Another CN patent owned by the Applicant, Patent No. ZL98220417.5 (Title: a permanent magnet operation mechanism for vacuum switch) discloses an operating mechanism that uses electromagnetic force to perform switch-off/switch-on and uses magnetic force of a permanent magnet to perform locking operation. Such an operating mechanism has simple structure and low failure rate. However, the operating mechanism has deficiencies that due to extremely large attraction force of the permanent magnet, once the electromagnet coil and the trip circuit have malfunction, it may be difficult to perform emergency switch-off manually, and the manual switch-off mechanism based on common lever principle cannot ensure stable switch-off speed. The essence of the permanent magnet operating mechanism is to allow an output shaft to perform axial motion, so as to perform switch-off/switch-on actions. However, up to now there has not been a manual switch-off device that is simple, reliable and that complies with the technical requirements in the field.